1. Field of the Invention
The present invention relates to a jitter measurement apparatus, a jitter measurement method, and a recording medium. The present invention particularly relates to a jitter measurement apparatus for measuring a jitter of a data signal having a substantially constant data rate.
2. Related Art
To measure a jitter of a data signal, which does not have constant intervals between data transitions, based on digital signal processing, a zero-crossing method can be used, which detects a timing at which the data signal crosses a 50% level (for example, a zero level) and measures a jitter of the data signal on the basis of the timing variation.
According to the zero-crossing method, the data signal is digitized at a predetermined sampling rate, and the zero-crossing timings of the data signal are detected based on the discrete values. Therefore, the measurement accuracy is dependent on how accurately the discrete values represent the zero-crossing timings (edge timings) of the data signal when the zero-crossing method is employed.
Considering this, the data signal needs to be digitized at a sampling rate which is sufficiently higher than the data rate of the data signal in order to measure the jitter of the data signal highly accurately by using the zero-crossing method. This means that the cost required for measuring the jitter of the data signal is driven up when high accuracy is desired with the use of the zero-crossing method.